How megadrought causes extensive mortality in a deep-rooted shrub species normally resistant to drought-induced dieback: The role of a biotic mortality agent.

Southern California experienced unprecedented megadrought between 2012 and 2018. During this time, Malosma laurina, a chaparral species normally resilient to single-year intense drought, developed extensive mortality exceeding 60% throughout low-elevation coastal populations of the Santa Monica Mountains. We assessed the physiological mechanisms by which the advent of megadrought predisposed M. laurina to extensive shoot dieback and whole-plant death. We found that hydraulic conductance of stem xylem (Ks, native ) was reduced seven to 11-fold in dieback adult and resprout branches, respectively. Staining of stem xylem vessels revealed that dieback plants experienced 68% solid-blockage, explaining the reduction in water transport. Following Koch's postulates, persistent isolation of a microorganism in stem xylem of dieback plants but not healthy controls indicated that the causative agent of xylem blockage was an opportunistic endophytic fungus, Botryosphaeria dothidea. We inoculated healthy M. laurina saplings with fungal isolates and compared hyphal elongation rates under well-watered, water-deficit, and carbon-deficit treatments. Relative to controls, we found that both water deficit and carbon-deficit increased hyphal extension rates and the incidence of shoot dieback.

Pleural and Pericardial Effusion With COVID-19 and Systemic Lupus Erythematosus and Its Recurrence: A Case Study.

As a chronic autoimmune disease, systemic lupus erythematosus (SLE) primarily affects young women and does not discriminate against any particular organs. In December 2019, coronavirus disease 2019 (COVID-19) spread worldwide, with many speculations of cardiac involvement in the pathogenesis of infection. Moreover, in cases where cardiac symptoms were described, they consisted solely of chest pain or a general deterioration in health if the patient presented with pleural effusion or pericardial effusion. Our patient, a 25-year-old Hispanic woman, initially complained of chest pain, cough, and shortness of breath. After being admitted, she noticed growing dyspnea and mild discomfort on the right side of her chest. The patient had both SLE and COVID-19 and had developed pleural and pericardial effusions. After two days in culture, nothing had grown from the fluid samples. In addition, measures of brain natriuretic peptide and total creatine kinase fell within the normal range. Considering the investigational findings, pericardiocentesis was performed. After the procedure, the patient's condition improved, and she was discharged. The patient continued taking CellCept® 1,500 mg and Plaquenil 200 mg and started taking colchicine. Her daily prednisone dose was increased to 40 milligrams. She felt well initially; however, after two weeks of follow-up, the pericardial effusion recurred, and pericardiocentesis was performed again. The patient was discharged in stable condition after a two-day hospital stay. After treatment of both initial and recurrent effusions, the patient's cardiac symptoms were resolved, and blood pressure became stable. We hypothesize that there may be other unreported cases of COVID-19-related viral pericarditis, pericardial effusion, and pericardial tamponade that could be caused by a combination of COVID-19 and a pre-existing condition, mainly autoimmune disorders. Due to the lack of clarity surrounding typical COVID-19 manifestations, it is crucial to record all cases of this unique illness and analyze any increased incidence of pericarditis, pericardial effusion, and pericardial tamponade in the public.

A Not So Common Iliac Vein Anomaly: A Case Report.

Arising from the external and internal iliac veins, the common iliac veins (CIVs) carry blood from the lower extremities and pelvic region into the inferior vena cava at the level of the fifth lumbar vertebra. It is sometimes common to observe slight anomalies in vascular anatomy in patients; however, anomalies of the CIVs are rare. We present a case of a patient with significant edema of the left lower extremity due to extrinsic compression (May-Thurner syndrome [MTS]) involving a duplicated left CIV found during vascular angiography. Anomalies in pelvic vasculature are well documented in the medical literature; however, documented cases of a duplicated CIV remain few and far between. These anomalies in pelvic vascular anatomy are essential to be aware of to avoid surgical complications and understand their implications in associated pathologies.

Presentation and Management of a Novel Ehlers-Danlos COL5A1 Variant With Birt-Hogg-Dube Syndrome: A Case Study.

Ehlers-Danlos syndrome (EDS) is a hereditary disorder caused by a mutation in the COL gene, which leads to the faulty synthesis of the collagen protein. EDS can present with a wide array of manifestations depending upon which COL gene is mutated. Birt-Hogg-Dubé (BHD) syndrome is a rare hereditary disorder currently identified in 200 families worldwide. It presents clinically with cutaneous, renal, and pulmonary manifestations due to an autosomal dominant mutation in a tumor suppressor gene, FLCN, on chromosome 17p11.2. We present a case of a 22-year-old male with Birt-Hogg-Dubé syndrome, showing typical features consistent with the classical type of EDS, with genetic testing revealing a COL5A1 mutation of "uncertain clinical significance", not yet reported in clinical literature. We discuss the treatment of this patient and describe the presentations of the two pathologies. Lastly, we put forth guidelines for the management of a dilated ascending aorta, with which this patient presents, for future patients who may present with this novel EDS mutation.

Human olfactory discrimination of genetic variation within Cannabis strains.

Cannabis sativa L. is grown and marketed under a large number of named strains. Strains are often associated with phenotypic traits of interest to consumers, such as aroma and cannabinoid content. Yet genetic inconsistencies have been noted within named strains. We asked whether genetically inconsistent samples of a commercial strain also display inconsistent aroma profiles. We genotyped 32 samples using variable microsatellite regions to determine a consensus strain genotype and identify genetic outliers (if any) for four strains. Results were used to select 15 samples for olfactory testing. A genetic outlier sample was available for all but one strain. Aroma profiles were obtained by 55 sniff panelists using quantitative sensory evaluation of 40 odor descriptors. Within a strain, aroma descriptor frequencies for the genetic outlier were frequently at odds with those of the consensus samples. It appears that within-strain genetic differences are associated with differences in aroma profile. Because these differences were perceptible to untrained panelists, they may also be noticed by retail consumers. Our results could help the cannabis industry achieve better control of product consistency.

Safety and tolerability of AAV8 delivery of a broadly neutralizing antibody in adults living with HIV: a phase 1, dose-escalation trial.

Adeno-associated viral vector-mediated transfer of DNA coding for broadly neutralizing anti-HIV antibodies (bnAbs) offers an alternative to attempting to induce protection by vaccination or by repeated infusions of bnAbs. In this study, we administered a recombinant bicistronic adeno-associated virus (AAV8) vector coding for both the light and heavy chains of the potent broadly neutralizing HIV-1 antibody VRC07 (AAV8-VRC07) to eight adults living with HIV. All participants remained on effective anti-retroviral therapy (viral load (VL) <50 copies per milliliter) throughout this phase 1, dose-escalation clinical trial ( NCT03374202 ). AAV8-VRC07 was given at doses of 5 × 1010, 5 × 1011 and 2.5 × 1012 vector genomes per kilogram by intramuscular (IM) injection. Primary endpoints of this study were to assess the safety and tolerability of AAV8-VRC07; to determine the pharmacokinetics and immunogenicity of in vivo VRC07 production; and to describe the immune response directed against AAV8-VRC07 vector and its products. Secondary endpoints were to assess the clinical effects of AAV8-VRC07 on CD4 T cell count and VL and to assess the persistence of VRC07 produced in participants. In this cohort, IM injection of AAV8-VRC07 was safe and well tolerated. No clinically significant change in CD4 T cell count or VL occurred during the 1-3 years of follow-up reported here. In participants who received AAV8-VRC07, concentrations of VRC07 were increased 6 weeks (P = 0.008) and 52 weeks (P = 0.016) after IM injection of the product. All eight individuals produced measurable amounts of serum VRC07, with maximal VRC07 concentrations >1 µg ml-1 in three individuals. In four individuals, VRC07 serum concentrations remained stable near maximal concentration for up to 3 years of follow-up. In exploratory analyses, neutralizing activity of in vivo produced VRC07 was similar to that of in vitro produced VRC07. Three of eight participants showed a non-idiotypic anti-drug antibody (ADA) response directed against the Fab portion of VRC07. This ADA response appeared to decrease the production of serum VRC07 in two of these three participants. These data represent a proof of concept that adeno-associated viral vectors can durably produce biologically active, difficult-to-induce bnAbs in vivo, which could add valuable new tools to the fight against infectious diseases.

In Up to My Ears and Temporal Lobes: Effects of Early Life Stress on Epilepsy Development.

Epilepsy and stress are each significant concerns in today's society, bearing heavy impacts on mental and physical health and overall quality of life. Unfortunately, the intersection between these is potentially even more concerning, as stress is a frequent trigger of seizures and may contribute to neural hyperexcitability. A growing body of research suggests a connection between early life stress (occurring in the prenatal or postnatal stage) and later development of epilepsy. While the larger part of this literature suggests that early life stress increases vulnerability for epilepsy development, there are a number of interacting factors influencing this relationship. These factors include developmental stage at which both stressor and seizure assessment occur, type of stressor, sex effects, and type of seizure (convulsive or non-convulsive). Additionally, a number of potential mechanisms have been identified, including activation of the hypothalamic-pituitary-adrenal axis, neuroinflammation, altered inhibitory/excitatory balance, and temporal lobe structures. Developing a clearer understanding of this relationship between early life stress and epilepsy, the factors that influence it, and underlying mechanisms that may serve as targets for intervention is crucial to improving quality of life for persons with epilepsy.

Diagnosing Strongylus vulgaris in pooled fecal samples.

Strongylus vulgaris is the most pathogenic intestinal helminth parasite infecting horses. The migrating larvae in the mesenteric blood vessels can cause non-strangulating intestinal infarctions, which have a guarded prognosis for survival. Infections are typically diagnosed by coproculture, but a PCR test is available in some countries. While it is ideal to test horses individually, many veterinarians and clients wish to pool samples to reduce workload and cost of the diagnostic method. The purpose of this study was to determine if pooling of fecal samples would negatively impact diagnostic performance of the coproculture and the PCR for determination of S. vulgaris infection. Ten horses with strongylid eggs per gram (EPG) >500 and confirmed as either S. vulgaris positive or negative were selected as fecal donors. Eight pools with feces from five horses were created with 0%, 10 %, 20 %, 30 %, 40 %, 50 %, 80 %, and 100 % S. vulgaris positive feces. From each pool, 20 subsamples of 10 g each were collected and analyzed. Half of these samples were set up for coproculture and the other half for PCR. All pools containing 50 % or greater S. vulgaris positive feces were detected positive by both PCR and coproculture. In the pools with less than 50 % S. vulgaris positive feces, the PCR detected 33 positive samples compared to 24 with the coproculture. Three samples from the 0% pool were detected as low-level PCR positives, but this could be due to contamination. These results indicate that diagnosing S. vulgaris on pooled samples is reliable, when at least 50 % of the feces in a pool are from S. vulgaris positive animals. Since S. vulgaris remains relatively rare in managed horses, however, some diagnostic sensitivity is expected to be lost with a pooled sample screening approach. Nonetheless, pooled sample screening on farms could still be considered useful under some circumstances, and the PCR generally performed better at the lower proportions of S. vulgaris positive feces.

Precision and spatial variation of cyathostomin mucosal larval counts.

Cyathostomins are pervasive parasites of equids across the world. Larval stages encyst in the mucosa of the cecum, ventral and dorsal colon and can induce an inflammatory response leading to larval cyathostominosis, a life-threatening generalized typhlocolitis. Mucosal digestion is the only gold standard procedure for identifying and quantifying all larval stages. There is a lack of standardization of this technique and several aspects are ambiguous, such as precision of the method and the possibility of spatial variation of mucosal larval counts. The aim of this study was to estimate precision for enumeration of early third stage larvae (EL3) and late third stage/fourth stage (LL3/L4) larvae and investigate spatial variation of encysted counts within large intestinal organs. Six naturally infected and untreated horses aged 2-5 years were euthanized as part of an anthelmintic efficacy study, and the cecum (Cec), ventral colon (VC) and dorsal colon (DC) were collected. Each organ was rinsed, weighed, and visually separated into 3 equally sized sections. Two 5% tissue samples were collected from each section, a total of six replicates per organ. The mucosae were digested, and 2% examined under the microscope for presence of EL3 and LL3/L4 stage larvae. Overall, 59 % of the harvested larvae were EL3s, and 41 % were LL3/L4s. The ventral colons represented 45 % of the total organ weight, and contributed 37 and 41 % of the EL3s and LL3/L4s harvested, respectively. The Cec, representing only 27 % of the weight contributed 23 % of EL3s and 47 % of LL3/L4s. The DC represented 28 % of the total organ weight, and 28 % and 12 % of the total EL3s and LL3/L4s, respectively. Coefficients of variation varied from 33 to 183 % for EL3 counts and 38-245% for LL3/L4 counts. There were no statistically significant associations between EL3 counts and either organ or location. For LL3/L4 counts there were no statistically significant differences between the three locations within organs (p = 0.1166), but the DC had significantly lower counts than the other two organs (p < 0.0001). Increasing the number of mucosal replicates from each organ improved estimation, but required a considerably increased workload. In conclusion, mucosal larval cyathostomin counts are highly variable, complicating their use for treatment efficacy estimation.

Tactical Circuit Training Improves Blood Pressure and Vascular Health More Than Resistance Training.

Exercise training is known to reduce CVD risk factors; however, in tactical populations, like veterans and firefighters, the effects of different forms of exercise such as tactical circuit training (CT) or conventional resistance training (RT) is unclear. Thus, the purpose of this study was to compare changes in various CVD risk measures after 4-week tactical CT or RT programs. Thirty-seven firefighters (20 CT, 17 RT), 35% of whom were veterans, participated. Pre- and post-intervention measures included body fat (BF%), carotid artery intima media thickness (IMT), central and brachial BP, and indices of arterial stiffness (augmentation index, Aix@75), myocardial oxygenation (subendocardial viability ratio, SEVR), and endothelial function (flow-mediated dilation, FMD). Estimation of maximum oxygen consumption (VO2peak) for aerobic fitness, balance, muscular endurance, and strength were also compared. For the clinical laboratory values, there were no between group differences and the only within group change was found in triglyceride levels. Tactical CT lowered triglyceride levels by 24.2% (P < 0.05). Only tactical CT exercise lowered BP. Both brachial (4.6% reduction) and central (4.4 % reduction) systolic and diastolic SBP and DBP decreased with CT (all P ≤ 0.01). After training we found improvements in FMD and SEVR with tactical CT only. Percent FMD increased by 28.7% (P < 0.01) while SEVR increased by 4.4% (P < 0.05) in the tactical CT group. Fitness improved in both cohorts (P < 0.05). These data suggest that 4 weeks of a CT program improves several CVD-risk factors and may be more beneficial.

Human olfactory detection of packaged cannabis.

Olfactory detection of cannabis aroma by police officers can be the basis for warrantless searches of motor vehicles in many jurisdictions in the United States. The odor source in these cases is often dried cannabis flower contained in various casual wrappings as well as in more elaborate packaging. Here we investigate whether packaging format alters the detectability of the cannabis. Two cannabis strains and five packaging formats were evaluated. Untrained observers were presented with two containers and asked to identify, based only on smell, the container that held a sample of packaged cannabis (the other container held identical, but empty, packaging material). The results showed that open and casually packaged cannabis was identified with high accuracy, while material packaged in doubly vacuum-sealed plastic was correctly identified at rates no different from chance. The results may help address issues involving the detectability of cannabis aroma in law enforcement and other scenarios.

Effects of circuit exercise training on vascular health and blood pressure.

As the global burden of cardiovascular disease (CVD) rises, public health-related interventions aimed at prevention of heart disease have gained medical attention. Clinical research reports that exercise is a protective risk factor associated with CVD and that clinicians need to provide exercise recommendations to patients. Nevertheless, physical inactivity remains a public health problem. In certain populations, like firefighters (FF), increased risk of CVD is especially concerning. The workload FF face is extreme, 50% of line-of-duty deaths (LODD) in FF are cardiac-related, and research on the volunteer FF population is scarce. Government regulations do not require volunteer FF companies to have fitness testing or programming, so exercise intervention studies are necessary to improve the burden of CVD risk in this population. Therefore, this study examined the effects of a 4-week exercise circuit training (CT) intervention on vascular health and fitness in volunteer FF (N = 27) from the Philadelphia PA area compared to a control group of Non-FF (N = 25). Carotid artery intima-media thickness (IMT), brachial artery flow-mediated dilation (FMD), augmentation index, and pulse pressure (PP), brachial and central blood pressure (BP) and fitness were measured pre- and post- intervention. Overall, volunteer FF had more significant improvements (p < 0.05) in vascular health measures (FMD, IMT, and PP). In both groups, we also found that brachial and central BP decreased with exercise. We show that a 4 week CT program can improve vascular structure and function in the volunteer FF population, suggesting that clinicians may be able to reduce or prevent cardiac LODD by exercise.

Consumer perceptions of strain differences in Cannabis aroma.

The smell of marijuana (Cannabis sativa L.) is of interest to users, growers, plant breeders, law enforcement and, increasingly, to state-licensed retail businesses. The numerous varieties and strains of Cannabis produce strikingly different scents but to date there have been few, if any, attempts to quantify these olfactory profiles directly. Using standard sensory evaluation techniques with untrained consumers we have validated a preliminary olfactory lexicon for dried cannabis flower, and characterized the aroma profile of eleven strains sold in the legal recreational market in Colorado. We show that consumers perceive differences among strains, that the strains form distinct clusters based on odor similarity, and that strain aroma profiles are linked to perceptions of potency, price, and smoking interest.

Management of Sigmoid Sinus Associated Pulsatile Tinnitus: A Systematic Review of the Literature.

OBJECTIVES: Although studies demonstrate 4 to 20% of patients with pulsatile tinnitus (PT) have associated sigmoid sinus anomalies, no consensus exists regarding optimal management. Our objective was to perform a systematic review exploring surgical and endovascular intervention of PT caused by sigmoid sinus anomalies. DATA SOURCES/EXTRACTION: A systematic review was performed using the Preferred Reporting Systems for Systematic Reviews and Meta-Analysis guidelines for reporting of results, with a target population encompassing patients with PT and either sigmoid sinus diverticulum or sigmoid wall dehiscence. From an initial search yielding 74 articles, 21 manuscripts met inclusion criteria. DATA SYNTHESIS: Of 139 patients, 90.4% were female. Mean age was 39.0 years. Diagnosis was sigmoid sinus diverticulum/aneurysm in 47.5% of patients, sigmoid sinus dehiscence in 35.3% of patients, and both in 17.3%. Sigmoid sinus wall reconstruction/resurfacing (SSW R/R) was used in 91.4% and endovascular procedures in 7.9% of patients. Postoperative recurrence was 3.5% (mean follow-up 21.1 m). Although there was no association between resolution rate and age or sex, right-sided PT resolved at a higher rate. For every increase in body mass index by 1 kg/m, the odds of PT resolution increased 9.2%. CONCLUSION: PT as a result of sigmoid sinus diverticula, aneurysms, and dehiscence is a rare, but largely treatable condition. Available interventions include SSW R/R, endovascular intervention, and cardiac U-clip techniques. In SSW R/R, bone pate, unspecified soft-tissue graft, and bone cement had the highest rates of PT resolution. While temporalis fascia and autologous bone chips were the materials most commonly used, they had significantly lower rates of PT resolution compared with the other materials, with the exception of auricular cartilage and bone cement. Most episodes of recurrence are resolved with medical management or a revision procedure. This study serves to summarize the current state of knowledge on the treatment of pulsatile tinnitus across disciplines.

Heart Rate and Blood Pressure Responses to Gear Weight Under a Controlled Workload.

OBJECTIVE: To compare the effects of personal protective equipment (PPE) weight on blood pressure (BP) and heart rate (HR), between volunteer firefighters (FF) and athletes. METHODS: Athletes and FF were matched by body size and came to the lab twice for two treadmill tests. The "Regular" test was completed in normal fitness clothing, and PPE test was completed in full structural PPE with monitoring of HR assessment every minute and BP each stage. RESULTS: In the FF cohort, all submaximal HR and BP levels were different. HRmax and VO2max were also different (all P < 0.05). In athletes, HRmax was higher in Regular test than PPE. CONCLUSIONS: Future research should examine the effect of different PPE weights on HR and BP responses.

Optimal duration of antimicrobial therapy for uncomplicated Gram-negative bloodstream infections.

PURPOSE: Optimal antimicrobial treatment duration for Gram-negative bloodstream infection (BSI) remains unclear. This retrospective cohort study examined effectiveness of short (7-10 days) and long (>10 days) courses of antimicrobial therapy for uncomplicated Gram-negative BSI. METHODS: Hospitalized adults with uncomplicated Gram-negative BSI at Palmetto Health hospitals in Columbia SC, USA from January 1, 2010 to December 31, 2013 were identified. Multivariate Cox proportional hazards regression with propensity score adjustment was used to examine risk of treatment failure in the two groups. RESULTS: During the study period, 117 and 294 patients received short and long courses of antimicrobial therapy for uncomplicated Gram-negative BSI, respectively. Overall, the median age was 67 years, 258 (63%) were women, 282 (69%) had urinary source of infection, and 271 (66%) had BSI due to Escherichia coli. The median duration of antimicrobial therapy was 8.5 and 13.3 days in the short and long treatment groups, respectively. After adjustment for the propensity to use a short course of therapy, risk of treatment failure was higher in patients receiving short compared to long courses of antimicrobial agents (HR 2.60, 95% CI: 1.20-5.53, p = 0.02). Other risk factors for treatment failure included liver cirrhosis (HR 5.83, 95% CI: 1.89-15.02, p = 0.004) and immune compromised status (HR 4.30, 95% CI: 1.57-10.80, p = 0.006). Definitive antimicrobial therapy with intravenous or highly bioavailable oral agents was associated with reduced risk of treatment failure (HR 0.33, 95% CI: 0.14-0.73, p = 0.006). CONCLUSIONS: The current results support common clinical practice of 2 weeks of antimicrobial therapy for uncomplicated Gram-negative BSI.

Carotid Artery IMT, Blood Pressure, and Cardiovascular Risk Factors in Males and Females.

Previous studies have investigated carotid artery intima-media thickness (IMT) and blood pressure and found a direct correlation between the two. It is known that adult females have better cardiovascular health than males until a certain stage of life, yet limited research has examined gender differences in vascular function. Thus, the purpose of this study was to investigate vascular structure and function, blood pressure, and blood glucose/cholesterol levels in relation to gender differences in young healthy adults. On three separate days, 44 adults (26.30 ± 11.9yrs; 24M, 20F) completed a carotid IMT ultrasound, a flow-mediated dilation (FMD), a fasted glucose and cholesterol test, a 24hr ambulatory blood pressure monitoring, a VO2max test, and a body composition measurement. Females had lower systolic blood pressure, lower diastolic blood pressure, lower LDL/HDL ratios, lower body mass index, a higher HDL count, and lower plasma glucose levels than males (p < 0.05 for all), all of which suggest better cardiovascular health. However, we found no gender differences in vascular health measures, IMT and FMD. Our results suggest that while young adult females have better cardiovascular health than males, endothelial function may not yet be affected in the young adult years.

Vascular Health in American Football Players: Cardiovascular Risk Increased in Division III Players.

Studies report that football players have high blood pressure (BP) and increased cardiovascular risk. There are over 70,000 NCAA football players and 450 Division III schools sponsor football programs, yet limited research exists on vascular health of athletes. This study aimed to compare vascular and cardiovascular health measures between football players and nonathlete controls. Twenty-three athletes and 19 nonathletes participated. Vascular health measures included flow-mediated dilation (FMD) and carotid artery intima-media thickness (IMT). Cardiovascular measures included clinic and 24 hr BP levels, body composition, VO2 max, and fasting glucose/cholesterol levels. Compared to controls, football players had a worse vascular and cardiovascular profile. Football players had thicker carotid artery IMT (0.49 ± 0.06 mm versus 0.46 ± 0.07 mm) and larger brachial artery diameter during FMD (4.3 ± 0.5 mm versus 3.7 ± 0.6 mm), but no difference in percent FMD. Systolic BP was significantly higher in football players at all measurements: resting (128.2 ± 6.4 mmHg versus 122.4 ± 6.8 mmHg), submaximal exercise (150.4 ± 18.8 mmHg versus 137.3 ± 9.5 mmHg), maximal exercise (211.3 ± 25.9 mmHg versus 191.4 ± 19.2 mmHg), and 24-hour BP (124.9 ± 6.3 mmHg versus 109.8 ± 3.7 mmHg). Football players also had higher fasting glucose (91.6 ± 6.5 mg/dL versus 86.6 ± 5.8 mg/dL), lower HDL (36.5 ± 11.2 mg/dL versus 47.1 ± 14.8 mg/dL), and higher body fat percentage (29.2 ± 7.9% versus 23.2 ± 7.0%). Division III collegiate football players remain an understudied population and may be at increased cardiovascular risk.

The effects of long (C20/22) and short (C18) chain omega-3 fatty acids on keel bone fractures, bone biomechanics, behavior, and egg production in free-range laying hens.

Keel fractures in the laying hen are the most critical animal welfare issue facing the egg production industry, particularly with the increased use of extensive systems in response to the 2012 EU directive banning conventional battery cages. The current study is aimed at assessing the effects of 2 omega-3 (n3) enhanced diets on bone health, production endpoints, and behavior in free-range laying hens. Data was collected from 2 experiments over 2 laying cycles, each of which compared a (n3) supplemented diet with a control diet. Experiment 1 employed a diet supplemented with a 60:40 fish oil-linseed mixture (n3:n6 to 1.35) compared with a control diet (n3:n6 to 0.11), whereas the n3 diet in Experiment 2 was supplemented with a 40:60 fish oil-linseed (n3:n6 to 0.77) compared to the control diet (n3:n6 to 0.11). The n3 enhanced diet of Experiment 1 had a higher n3:n6 ratio, and a greater proportion of n3 in the long chain (C20/22) form (0.41 LC:SC) than that of Experiment 2 (0.12 LC:SC). Although dietary treatment was successful in reducing the frequency of fractures by approximately 27% in Experiment 2, data from Experiment 1 indicated the diet actually induced a greater likelihood of fracture (odds ratio: 1.2) and had substantial production detriment. Reduced keel breakage during Experiment 2 could be related to changes in bone health as n3-supplemented birds demonstrated greater load at failure of the keel, and tibiae and humeri that were more flexible. These results support previous findings that n3-supplemented diets can reduce fracture likely by increasing bone strength, and that this can be achieved without detriment to production. However, our findings suggest diets with excessive quantities of n3, or very high levels of C20/22, may experience health and production detriments. Further research is needed to optimize the quantity and type of n3 in terms of bone health and production variables and investigate the potential associated mechanisms.